This invention relates to cellular telecommunications networks and more particularly to generating a desired quality-of-service (QoS) for communication between a communication unit and a service provider (i.e., a bearer such as a radio network) at call set-up or at handoff.
In a typical cellular communication network, a user defines his or her service requirements to a bearer (i.e., a service provider) in terms of one or more requested quality-of-service (QoS) vectors or requested service vector, RSV. Each vector consists of a number of QoS parameters which relate to the required service. Alternatively, a user""s requirements may be input into a computer or a computer application which performs the negotiation with the bearer. The QoS parameters may include, but are not limited to, required bit rate (peak, mean and/or some other rate), required bit error rate (BER) and required transmission delay. In addition, the user may also specify a price parameter for a desired service. For a given application, a range of values for each of these QoS parameters may be acceptable to the user. For example, in a web browsing application, a user normally desires a high bit rate for which the user is willing to pay a higher price. However, a user may tolerate a lower bit rate if the user is interested in minimizing the price. For some applications, the range of values for certain QoS parameters that the user is willing to accept may be relatively small. For example, in a voice application, the user may not be willing to tolerate a lower bit rate or a longer transmission delay because of the susceptibility of speech data to low bit rates and/or long delays. Under less than acceptable conditions, e.g., low bit rate and long delay, it may be preferable that the call be blocked.
One way the user can express its service requirements to the service provider is to define two QoS vectors, wherein the QoS parameter values in the first QoS vector represent a desired service, and wherein the QoS parameter values in the second QoS vector represent an acceptable (or minimum level of) service. Typically, the desired QoS parameter values indicate a lower price level sensitivity on behalf of the user, as suggested above. In contrast, the acceptable QoS parameter values are associated with a higher price level sensitivity. In the case of speech, the desired value and the acceptable value for certain QoS parameters (e.g., maximum transmission delay) may be the same, thus indicating a user""s unwillingness to accept less than desired values for those QoS parameters. The at least two QoS vectors containing the desired and acceptable QoS parameter values may be expressed as:
QoSdesired=(bit ratemaximum, delayminimum, . . . , pricedesired)
QoSminimum=(bit rateminimum, delaymaximum, . . . , priceacceptable)
Alternatively, a user may define for the service provider a set of QoS vectors, QoS1 . . . QoSn, wherein the combination of QoS parameter values in vector QoS1 represent a desired service, wherein the combination of QoS parameter values in vector QoSn represent a minimum, but acceptable service, and wherein the combination of QoS parameter values in vectors QoS2 to QoSnxe2x88x921 represent acceptable service that is less than the desired service but better than the minimum acceptable service. In the web browsing application, for example, each of the vectors QoS1 to QoSN might contain a different bit rate value. For the speech application, however, each of QoS vectors QoS1 to QoSn may contain the same bit rate value, once again, exemplifying that with speech data, a user is generally less likely to accept a QoS that is less than the desired QoS. The set of QoS vectors QoS1 to QoSN may be expressed as:
QoS1=(bit rate1, delay1, . . . , price1)
xe2x80x83QoS2=(bit rate2, delay2, . . . , price2)
QoS3=(bit rate3, delay3, . . . , price3)
QoS4=(bit rate4, delay4, . . . , price4)
QoSn=(bit raten, delayn, . . . , pricen)
At call set-up, handover and call re-negotiation, a determination has to be made as to which service will be used to establish a connection. The requirements of the user and the capability of the bearer have to be taken into account. The capability of the bearer is also expressed in the form of a QoS vector and may be referred to as an offered service vector, OSV. The procedure that results in generation of an OSV is known as a bearer service generation. The procedure that attempts to match user requirements with bearer capabilities is known as a bearer service negotiation. The bearer service negotiation process results in the generation of a negotiated QoS vector or NSV. In general, a NSV contains QoS parameter values that reflect the service which the service provider is capable of providing and which satisfy requirements of the user specified values in a RSV. In the event that no match between the requirements of the user and the capability of the bearer is established, the NSV is said to be empty.
A service provider cannot always guarantee the quality of service defined by the NSV. In actuality, the QoS parameter values in the NSV merely represent the service which the service provider will attempt to achieve for the user at call set-up, handover or call re-negotiation. However, during the time period between the bearer service negotiation and, for example, call set-up, conditions may change due to such phenomena as data traffic fluctuation and fading, thereby making it impossible for the service provider to achieve the level of service defined by the NSV. If the service provider cannot, in fact, achieve at least the user""s minimum acceptable service requirements, the bearer service has to be renegotiated, or in the case of an on-going call, handed over (i.e., to a different service provider) or dropped.
With data services being added to cellular networks, wireless systems engineering is faced with the task of having to accommodate connections belonging to different services each of which may have a different quality requirement. In a complex mixture of different applications using wireless access in 2nd generation system (such GSM, TDMA/136, etc.,), WCDMA and wireless LANs, lack of structured service handling will result in a low system performance and create added difficulty to operators managing networks.
Full rate and half rate speech is currently available in commercial GSM systems and circuit switched data will soon extend to multiple slot transmission. Admission control (which controls access to a service) of these mixed services, though possible, is rudimentary since there are few service types. In addition, load of services other than full rate speech is low. Attempts to address mixed services wireless systems have focused on the task of allocating radio resources to a delay-critical service such as speech and a non-delay critical service such as data according to a predefined access protocol.
Several problems exist in current solutions for handling mixed services. These problems are treated on a service-by-service basis without an overall structure which leads to difficulties in a system supporting a complex mix of services.
For admission control, service differentiation and user differentiation are not covered extensively. That is, there may be resources available for one service but not for another and it may be available for one important user but not for another.
Adaptive applications, i.e., application with multiple operation modes, are not well covered either. A video codec, for example, can operate in multiple bit rate modes. These modes correspond to the bandwidth available, and hence bandwidth negotiation has to take place at least at connection setup.
Elastic applications, such as web browsing, which can operate in a single mode using a variety of bearers (and give the user a corresponding variety of quality) have also not been treated extensively.
What is desired, therefore, is a solution for handling mixed services which is adaptive in order to accommodate applications having multiple operating modes as well as for handling elastic applications.
According to exemplary embodiments, a telecommunication control system for handling a range of data transfer rates within a network is disclosed. The system comprises: an application interpreter for generating at least one bearer request; an admission control apparatus for matching the at least one bearer request with at least one offered bearer to produce a negotiated bearer; and a radio resource manager for receiving the negotiated bearer and maintaining a level of quality specified in said bearer request.
According to other exemplary embodiments, a method for performing an admission control function in a telecommunication system handling a range of data rates is disclosed. The method comprises the steps of: generating at least one offered bearer by a bearer generator in response to a request for a bearer; matching the requested bearer with the generated bearer; and providing a negotiated bearer wherein the negotiated bearer results from the matching of the requested bearer with the generated bearer.